RFR: 8266749: AArch64: Backtracing broken on PAC enabled systems

[Vladimir Kempik]

On Fri, 14 May 2021 14:50:13 GMT, Vladimir Kempik <vkempik at openjdk.org> wrote:

> let me check with macos/aarch64 on macos11.4b as it was giving problems with return address having pac signature sometimes too.
> 
> Nop, still crashes in SharedRuntime::raw_exception_handler_for_return_address with return address having pac signature in it (probably it's pac, not 100% sure), will investigate further

on macos11.4b it's getting something that looks like PAC-ed pointer in src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 487
  address generate_forward_exception() {
...
    __ mov(c_rarg1, lr);  <-- here
not sure how it got here bypassing all of your checks

maybe it's too early as 11.4 is still beta. ( beta3 ) and java_m1 is not arm64e process (arm64e = arm64 + PAC)

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PR: https://git.openjdk.java.net/jdk/pull/4029